An Open Label, Randomised, Repeat Dose Study to Assess the Pharmacokinetic Performance of Five Ezogabine/Retigabine Modified Release (MR) Formulations at Steady State Compared to the Immediate Release (IR) Formulation.

This is an open-label, single centre, repeat dose, up- titration study in healthy male and female subjects to assess the pharmacokinetic (PK) performance of five prototypes of ezogabine modified release tablet formulations. The study will consist of a screening period, a treatment phase (consisting of a titration phase, bioavailability phase and food effect phase) and a post-treatment follow-up visit. The study duration from screening to follow up will be approximately 7 weeks. No study procedures will start before informed consent is obtained. Subjects will remain in the clinical unit for the duration of the treatment period (35 days). Subjects will receive repeat doses of ezogabine for up to 34 days starting at a dose of 100 mg IR TID (300mg TDD) with a standard meal (to be consumed 30 min prior to dosing) for Days 1-3, on days 4-6 subjects will receive 150mg IR TID (450mg TDD). On Day 7 through to the end of the study subjects will receive ezogabine (Mr or IR) at a dose of 600mgTDD. On Day 7 subjects will enter into a 6-way cross over period to investigate the 5 MR formulations being tested (each at 300mg BID) and the single IR formulation (at 200mg TID). Subjects will receive each formulaition for 4 days and blood samples for pharmacokinetic analysis will be collected up to 24 hours post dose on each 4th day (PK days). On Day 31 subjects will enter into a food effect phase to investigate the 5 MR formulations being tested (each at 600mg QD). Subjects in this period will have a PK day on Day 33 (following a standard breakfast), and on Day 34 (following a high fat breakfast) to investigate a food effect on the PK profile of ezogabine.